VITAMIN-E SERUM LEVELS IN PATIENTS WITH CHRONIC RENAL-INSUFFICIENCY

Vitamin E is a fat soluble vitamin with antioxidative properties. Under physiological conditions deficiency states have been recognized only in gastrointestinal diseases with excessive disturbances of fat absorption. Patients with chronic and terminal renal insufficiency may have an altered requirement for vitamin E. This can be a result of dietary restriction, special composition of the diet, metabolic disturbances, the effect of various medicaments, the extent of remaining renal function as well as possible losses through the dialysis membrane. The recommendations given in the literature for supplementation with vitamin E in chronic renal insufficiency are contradictory. In 27 patients with moderate and advanced chronic renal insufficiency (serum creatinine 407.7 +/- 202-mu-mol/l), 21 dialysis patients (duration of dialysis 4 - 50 months, frequency 18 - 22m2 h/week) and 27 healthy controls, vitamin E was measured spectrophotometrically in serum and correlated with parameters of renal function, hematological values, protein and lipid concentration as well as parameters of dialysis strategy. In addition dialysance studies were done in dialysis patients. The -mean serum vitamin E levels in both patient groups (chronic renal insufficiency 12.1 +/-1.2-mu-g/ml, dialysis patients 7.2 +/- 0.8-mu-g/ml) were raised in comparison to normal subjects (4.6 +/- 0.7-mu-g/ml). There was no significant relationship between serum vitamin E levels and urea, creatinine, Hb, hematocrit, serum protein or form and duration of dietetic as well as dialysis therapy. Calculation of the vitamin E content of the different protein diet regimes (40, 60, 80 g/day) provided no evidence of deficiencies in the supply of vitamin E. The dialysance studies showed that during dialysis vitamin E was not extracted. Vitamin E could not be found in the dialysate. On the basis of these results, the uremic syndrome seems not to be accompanied by a vitamin E deficiency. Supplementation of these patients is not a conspicuous necessity. Although low levels of vitamin E are not necessarily the equivalent of a biological deficiency, conversely, normal or raised levels, do not exclude this possibility. In the future, due to the close relationship and interaction with the fat metabolism, only the quotient of vitamin E and serum lipid concentration (triglyceride or HDL-cholesterol) should be made use of. This aspect is just as important for therapeutic conclusions as the search for and consideration of factors with oxidative properties.